Japanese Laid-Open Patent Publication No. 2007-192831 discloses a diagnostic kit capable of avoiding the need for invasive tests or the use of a blood marker in the measurement of glucose regulation. Such diagnostic kit is a diagnostic kit for measuring blood sugar regulation in a subject and includes a predetermined amount of enriched 13C glucose and a respiration sampling container. The diagnostic kit includes a plurality of respiration sampling containers in one embodiment, is used for diagnosing diabetes in another embodiment, and is used for diagnosing insulin resistance in yet another embodiment.